The invention relates to parking assistance systems having at least automatic lateral guidance for motor vehicles, particularly for automobiles.
In parking assistance systems with automatic lateral guidance, steering of the motor vehicle during the parking procedure is undertaken by the system. Longitudinal guidance needs to be undertaken by the driver himself by means of appropriate acceleration and braking. In parking assistance systems with automatic lateral guidance and automatic longitudinal guidance, the task of longitudinal guidance is also undertaken by the parking assistance system in part or in full depending on the degree of automation of the longitudinal guidance. In parking assistance systems with automatic lateral guidance and fully automatic longitudinal guidance, the steering, the brakes, the vehicle drive and the direction of travel (forward or reverse travel), for example, are controlled by the parking assistance system. In such parking assistance systems, the driver has the option, for example, of operating an operator control element, for example a key, in order to be able to have the vehicle parked and optionally removed from a parking space automatically.
An exemplary parking assistance system with automatic lateral guidance and fully automatic longitudinal guidance is described in the document “Parkassistent mit Längsund Querführung”, Dirk Ahrens, 5. Driver Assistance Conference of TU München, Munich, 2012, which is available on the Internet under the link “http://mediatum.ub.tum.de/doc/1142099/1142099.pdf”, for example.
Such parking assistance systems allow parking in parallel parking spaces and/or perpendicular parking spaces.
The invention relates to a parking assistance system having at least automatic lateral guidance for parking in perpendicular parking spaces.
By way of example, in order to park in perpendicular parking spaces, such parking assistance systems involve ultrasonic sensors being used when manually traveling past motor vehicles parked perpendicular to the road to automatically measure a perpendicular parking space between the vehicles parked in a perpendicular direction. Based on the measurement of the parking space, performance of the parking maneuver is preceded by a parking trajectory being planned, on which the vehicle parks in the parallel parking space in reverse with automatic lateral guidance and possibly automatic longitudinal guidance in one or more moves. If, during the trajectory planning, it is established that it is not possible to satisfy the criteria for an admissible parking end position in a single parking move in a reverse direction (for example in relation to the distance from the vehicles bounding the perpendicular parking space and in relation to the rotation between the vehicle orientation and the orientation of the parking space), then there is a need for a subsequent corrective move in a forward direction with a subsequent parking move in a reverse direction. Alternatively, multiple corrective moves in a forward direction with a respective subsequent parking move in a reverse direction may be necessary.
The corrective moves that may be necessary involve the vehicle being driven forward out of the perpendicular parking space again to a greater or lesser extent into the traffic area. Depending on the extent to which the vehicle has already entered the perpendicular parking space at the beginning of the corrective move, it can occur that the driver would no longer have a clear view of the following traffic in the traffic area at the beginning of the corrective move in a forward direction on account of the visual obstruction by a vehicle bounding the perpendicular parking space. In this case, the vehicle would travel into the traffic area without a view of the following traffic; in a parking assistance system with only automatic lateral guidance, the driver then receives from the system a request (typically by means of a display unit in the vehicle cockpit) to drive forward, and in a parking assistance system with automatic longitudinal guidance, this driving forward into the traffic area would even be effected fully automatically. Typically, such systems have no sensors for identifying in sufficient time following cross traffic traveling at speed in order to abort the corrective move in a forward direction in the event of a risk of collision with the following cross traffic. This is aggravated by the fact that the following traffic, particularly even cyclists, notice too late that a vehicle that has already entered the perpendicular parking space is pulling out.
Alternatively, similar parking assistance systems are naturally also possible in which the vehicle parks in the perpendicular parking space forward and any corrective moves are effected in a reverse direction rather than in a forward direction. The explanations above regarding reverse parking also apply mutatis mutandis to parking assistance systems for parking in perpendicular parking spaces in a forward direction.
It is an object of the invention to improve an automated parking procedure into a perpendicular parking space such that an accident with the following traffic is prevented.
This and other objects are achieved by a method for avoiding accidents with following traffic during an automated parking procedure in accordance with embodiments of the invention.
A first aspect of the invention relates to a method for avoiding accidents with the following traffic during an automated parking procedure for a motor vehicle having a parking assistance system with at least automatic lateral guidance. The parking assistance system can additionally comprise automatic longitudinal guidance with drive control and control of the direction of travel (forward or reverse direction). For parking, a parking move into the perpendicular parking space is effected in a reverse or forward direction, and, when required, subsequently at least one corrective move is effected in a forward or reverse direction.
The method involves determining that there is a need for a corrective move in a forward or reverse direction. This can be effected during the actual trajectory planning prior to the parking move in a reverse direction. To this end, it is possible to determine a trajectory of travel for the parking move with a particular parking end position at the end of the trajectory of travel of the parking move, for example. The parking end position is then rated in relation to one or more criteria for an admissible parking end position being satisfied, e.g. in relation to an admissible distance from the vehicles bounding the perpendicular parking space in the parking end position and in relation to the rotation between the vehicle orientation in the parking end position and the orientation of the parking space. This then involves determining a need for a corrective move by finding that a criterion necessary for an admissible parking end position is not satisfied and hence there is a need for a corrective move.
In response to a need for a corrective move being established, the vehicle is prevented, during the parking move, from entering the perpendicular parking space to such a depth that the driver would subsequently no longer have a clear view of the following traffic at the beginning of the corrective move in a forward or reverse direction on account of the visual obstruction by a vehicle bounding the perpendicular parking space. By way of example, it is possible to continually check whether the parking move in a reverse direction results in the perpendicular parking space being entered to an excessive depth when there is a need for at least one corrective move in a forward direction.
If, by contrast, it is established that there is no need for a corrective move, then the vehicle is parked in the parking space in the planned parking move in a forward direction or reverse direction up to the previously planned parking end position (either manually by virtue of appropriate instructions for manual longitudinal guidance to the driver or using automatic longitudinal guidance).
In order to prevent the vehicle from entering the perpendicular parking space to such a depth during the parking move that subsequently the driver would no longer have a clear view of the following traffic at the beginning of the corrective move in a forward or reverse direction on account of the visual obstruction by a vehicle bounding the perpendicular parking space, the parking move can be terminated at such an early stage, for example, and a change of direction can be triggered before the position of the driver crosses the line of sight (either manually by virtue of appropriate instructions for manual longitudinal guidance to the driver or using automatic longitudinal guidance). The line of sight is typically formed by the rear or front, facing the traffic area, of one or more vehicles bounding the perpendicular parking space.
The fact that the vehicle does not enter the perpendicular parking space to such a depth during the parking move also allows the following traffic to see the parking vehicle during almost the whole parking procedure up to shortly before the parking end position is reached; this prevents the vehicle from disappearing in the perpendicular parking space for a short time during the reverse parking move and then no longer being visible to the following traffic.
The parking move may be the first parking move in a reverse direction or a later parking move in a reverse direction (after a corrective move in a forward direction has already been performed beforehand), for example.
It is advantageous if—while the parking move is being effected—it is continually monitored to what depth the vehicle has already entered the parking space. During the monitoring, it is then established at one time or another that the vehicle has already entered the parking space to a particular first limit or beyond a particular first limit. In response to this finding, premature termination of the parking move and performance of a corrective move in a forward or reverse direction are caused. The premature termination of the parking move means that the planned trajectory of this parking move is not taken up to the planned end point of the parking move.
By way of example, the parking assistance system may be a parking assistance system having automatic lateral guidance, but without automatic longitudinal guidance for the purposes of automatic drive control and automatic control of direction-of-travel changes. The system triggering premature termination of the parking move and performance of a corrective move then comprises asking the driver to travel forward or to reverse, for example. The request can be made visually by means of a display unit in the vehicle cockpit, for example. To trigger premature termination of the parking move, for example, the display unit is used to output the notification “Please travel forward”. The driver will then brake and subsequently, at a standstill, change the direction of travel (for example by moving the gear selector lever of an automatic gearbox from R to D or moving the gear selector lever of a manual gearbox from R to first gear).
Alternatively, a parking assistance system may have automatic lateral guidance and automatic longitudinal guidance (with automatic drive control and automatic control of direction-of-travel changes), for example. To prematurely terminate the parking move and perform a corrective move, the vehicle is automatically slowed to a standstill, the direction of travel is automatically changed (for example by shifting the automatic gearbox from reverse to forward) and the corrective move is automatically performed by virtue of appropriate control of the vehicle drive.
The first aspect of the invention prevents the vehicle from entering a parking space to an excessive depth and the driver from then not being able to see the traffic area during a subsequent corrective move. Furthermore, the vehicle therefore remains visible to the following traffic during the parking procedure up until shortly before the parking end position is reached.
By contrast, a second aspect of the invention relates to the case of the vehicle already having entered the parking space to an excessive depth. In this regard, during the parking maneuver (preferably during the parking move in a reverse or forward direction), the depth to which the vehicle has already entered the parking space is continually monitored. It is then established at some time or another that the vehicle has already entered the parking space to a particular second limit or beyond a particular second limit. This means that the vehicle has already entered the parking space to an excessive depth.
In response to this finding, a corrective move in a forward or reverse direction is prevented, even though there is actually a need for a corrective move (since the parking move cannot be used to reach a parking end position that is admissible in terms of the criteria described above).
As soon as a point of no return has been exceeded, for example, a corrective move in a forward direction out of the parking space is prevented. By way of example, the point of no return can correspond to a line of sight into the flowing traffic or to the line of sight plus a particular positive or negative offset (e.g. 20 cm or −20 cm).
In a parking assistance system with automatic longitudinal guidance, the prevention can involve no further corrective move out of the parking space being performed automatically during the parking maneuver.
In a parking assistance system without automatic longitudinal guidance, on the other hand, the prevention of the corrective move can involve preventing a request to the driver to travel forward or to reverse from being output. Furthermore, it is also possible for a warning notification to be output to the driver.
The first and second aspects of the invention can also be combined. In this case, a preferred embodiment of the invention provides for the second limit to be situated deeper in the parking space than the first limit (i.e. in the case of a parking move in a reverse or forward direction, the first limit can be reached before the second limit is reached).
It is subsequently assumed that the parking assistance system does not have automatic longitudinal guidance. According to the first aspect of the invention, in response to the finding that the vehicle has already entered the parking space to a particular first limit or beyond a particular first limit, the driver is asked to travel forward or to reverse (i.e. the parking move in reverse or forward is intended to be terminated prematurely). If the driver continues the parking move despite a request by the system, on the other hand, then the second aspect of the invention takes effect: that is to say that subsequently, in response to the finding that the vehicle has already entered the parking space to a particular second limit or beyond a particular second limit during the parking move, the request to the driver to travel forward or to reverse is withdrawn. By way of example, when the first limit is crossed, the request “Please travel forward” is output to the driver. If this request is ignored, then this request ceases again when the second limit is crossed. It would instead be possible for a request to reverse or travel forward to be output to the driver directly even when the second limit is crossed.
It would also be contemplated for, after the request to the driver to travel forward or to reverse is withdrawn in the event of the driver traveling in a forward direction or reverse direction, the parking assistance function (i.e. the automatic steering function thereof) to be aborted, for example when the second limit is reached or crossed in a forward direction or reverse direction. Optionally, it is then also possible for an error notification to be delivered to the driver.
The text above has indicated in relation to both aspects of the invention that the criterion that the vehicle has entered the parking space to a particular limit or beyond a particular limit is checked for satisfaction. In the case of the first aspect of the invention, the first limit is involved, and in the case of the second aspect of the invention, the second limit is involved. Satisfaction of this criterion is consistent, by way of example, with the situation when a reference point on the vehicle reaches or crosses a line of sight or crosses the line of sight with a particular (positive or negative) offset (e.g. +20 cm or −20 cm). In this case, the line of sight is preferably formed by the rear or front, facing the traffic area, of one or more vehicles bounding the perpendicular parking space. By way of example, the vehicle comprises a B pillar on each vehicle side, and the reference point is situated between the two B pillars. Thus, a check is then performed to determine whether this reference point between the two B pillars reaches or crosses the line of sight, possibly with a particular offset.
The invention also relates to a parking assistance system that is configured to avoid accidents with the following traffic in accordance with the first aspect of the invention. It is capable of finding that there is a need for a corrective move in a forward or reverse direction, and, in response thereto, preventing the vehicle from entering the perpendicular parking space to such a depth during the parking move that subsequently the driver would no longer have a clear view of the following traffic at the beginning of the corrective move in a forward or reverse direction on account of the visual obstruction by a vehicle bounding the perpendicular parking space.
The above explanations relating to the method according to the invention based on the first aspect of the invention also apply in a corresponding manner to the parking assistance system described above. Exemplary embodiments of the parking assistance system that are not described explicitly at this juncture correspond to the described exemplary embodiments of the method according to the invention based on the first aspect of the invention.
The invention also relates to a parking assistance system that is configured to avoid accidents with the following traffic in accordance with the second aspect of the invention. It is capable of monitoring to what depth the vehicle has entered the parking space, and of determining that the vehicle has already entered the parking space to a particular second limit or beyond a particular second limit. It is furthermore capable of responding to this finding by preventing a corrective move in a forward or reverse direction despite the need for a corrective move.
The explanations above relating to the method according to the invention based on the second aspect of the invention also apply in a corresponding manner to this parking assistance system. Exemplary embodiments of the parking assistance system that are not described explicitly at this juncture correspond to the described exemplary embodiments of the method according to the invention based on the second aspect of the invention.
A preferred exemplary embodiment of a parking assistance system according to the invention is configured to avoid accidents with the following traffic in accordance with the two aspects of the invention, as has been described in detail above for the two aspects.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of one or more preferred embodiments when considered in conjunction with the accompanying drawings.